What valve springs should I use?

MOPEkidD-3 said
You get those Magnum heads checked for cracks?

Yes, I checked them while ejoying a Hamm's beer after work. :). In all seriousness, the heads were free, I got 2 free sets for helping clean out a guy's old shop. I did not see any visible cracks or any signs of coolant leaking, just typical carbon.